Specifically, UAVs can be used to carry deployable BSs to provide additional or on-demand coverage to users, especially when providing MC services, thanks to their good mobility and higher chances of light-of-sight (LOS) propagation. However, there are a number of challenges when implementing UAV-BS assisted wireless communication networks in practice [1]}[2]}. The system performance and user experience are significantly impacted by the deployment and configuration of a UAV-BS, including the UAV’s flying altitude, operation time, antenna capabilities, transmit power, etc. While optimizing these parameters to provide on-demand access services, it is also necessary to maintain a good backhaul link between the UAV-BS and traditional BSs on the ground. The optimization problem becomes even more complicated when considering different system loads and dynamic user distribution. In some cases where multiple UAV-BSs are needed to cover a wide area, the complexity of providing reliable and scalable backhaul links between different UAV-BSs will further increase.
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